[netdrvr] Use dev_printk() when ethernet interface isn't available

For messages prior to register_netdev(), prefer dev_printk() because
that prints out both our driver name and our [PCI | whatever] bus id.

Updates: 8139{cp,too}, b44, bnx2, cassini, {eepro,epic}100, fealnx,
	 hamachi, ne2k-pci, ns83820, pci-skeleton, r8169.

Signed-off-by: Jeff Garzik <jeff@garzik.org>